In general, an anti-reflective film (anti-glare film) is disposed to minimize the reflection of external light on the screen of display devices such as PDP, CRT, and LCD.
The conventional anti-reflective coating film is commonly formed by disposition of an anti-reflective layer on a light-transparent substrate. In this regard, the most widely used anti-reflective layer has a three-layer structure of a hard coat layer and high and low refractive index layers sequentially laminated from the light-transparent substrate. Recently, a two-layer structure omitting the hard coat layer or the high refractive index layer from the anti-reflective layer has been commercialized, in order to simplify the production process. In order to provide anti-glare and scratch-resistant properties, the anti-reflective coating film provided with an anti-glare hard coat layer has been also used.
Meanwhile, the anti-reflective coating film is commonly manufactured by a dry or wet method. Of the methods, the dry method is to laminate a plurality of thin layers using deposition or sputtering. This method offers superior adhesion at a layer interface, but requires high production cost, which is a limitation to commercial use.
In contrast, the wet method is to dry and cure a composition comprising a binder, a solvent, etc., after applying it onto a substrate. This method is less expensive than the dry method, and thus widely used in commercial applications. In the wet method, however, compositions required for the formation of the hard coat layer and the high and low refractive index layers should be prepared separately, and each layer is sequentially formed using the composition. Thus, the production process becomes complicated, and offers weak adhesion at a layer interface.
For this reason, many studies have been actively made to develop an anti-reflective coating composition capable of forming two or more layers by a single wet coating process. However, there are still many problems that phase separation does not properly occur upon applying the compositions during the production process, and thus individual layers deteriorate in functions.
Further, the hard coat layer or the high refractive index layer is typically formed on the substrate as a pure binder or as a separate layer comprising the binder and inorganic nanoparticles, and the hollow particle-dispersed low refractive index layer is formed thereon. However, there are still problems that the anti-reflective coating film having this structure has low durability because of weak adhesion at a layer interface.